Prosecutors called Chi Mak the “perfect sleeper agent,” though he hardly looked the part. For two decades, the bespectacled Chinese-born engineer lived quietly with his wife in a Los Angeles suburb, buying a house and holding a steady job with a U.S. defense contractor, which rewarded him with promotions and a security clearance. Colleagues remembered him as a hard worker who often took paperwork home at night.

Eventually, Mak’s job gave him access to sensitive plans for Navy ships, submarines and weapons. These he secretly copied and sent via courier to China — fulfilling a mission that U.S. officials say he had been planning since the 1970s.

The Chinese government, in an enterprise that one senior official likened to an “intellectual vacuum cleaner,” has deployed a diverse network of professional spies, students, scientists and others to systematically collect U.S. know-how, the officials said. Some are trained in modern electronic techniques for snooping on wireless computer transactions. Others, such as Mak, are technical experts who have been in place for years and have blended into their communities.

“Chi Mak acknowledged that he had been placed in the United States more than 20 years earlier, in order to burrow into the defense-industrial establishment to steal secrets,” Joel Brenner, the head of counterintelligence for the Office of the Director of National Intelligence, said in an interview. “It speaks of deep patience,” he said, and is part of a pattern.

Women seeking a lifelong mate might do well to choose the guy a notch below them in the looks category. New research reveals couples in which the wife is better looking than her husband are more positive and supportive than other match-ups.

The reason, researchers suspect, is that men place great value on beauty, whereas women are more interested in having a supportive husband.

A group of trained “coders” rated the facial attractiveness of each spouse on a scale from 1 to 10, with the perfect 10 representing the ultimate babe. About a third of the couples had a more attractive wife, a third a more attractive husband and the remaining partners showed matching looks.

In couples with more attractive husbands, both partners were less supportive of one another. McNulty suggests wives mirror, in some ways, the level of support they get from husbands.

“The husband who’s less physically attractive than his wife is getting something more than maybe he can expect to get,” McNulty told LiveScience. “He’s getting something better than he’s providing at that level. So he’s going to work hard to maintain that relationship.”